C. P. Ononugbo

Bio: C. P. Ononugbo is an academic researcher from University of Port Harcourt. The author has contributed to research in topics: Radionuclide & Sediment. The author has an hindex of 7, co-authored 22 publications receiving 115 citations. Previous affiliations of C. P. Ononugbo include Federal University of Petroleum Resource Effurun.

Impact of Gas Exploitation on the Environmental Radioactivity of Ogba/Egbema/Ndoni Area, Nigeria

Abstract: A key component of the current national energy policy of Nigeria is to efficiently utilize her abundant natural gas reserves, especially in the energy sector. This paper reports a study of the terrestrial radioactivity in the industrial areas of Ogba/Egbema/Ndoni Local Government Area (ONELGA) of Rivers State. These industrial areas and their host communities were divided into six (6) zones, each having an oil and gas facility. An in-situ measurement was done using two well calibrated nuclear radiation meters (digilert-100 and digilert-50) and geographical positioning system (GPS). Ten readings were taken in each of the six zones and the host community at randomly selected sites, making a total of 60 sampling points. The mean site radiation level ranges from 0.014 ± 0.001mRh-1 (1.183 ± 0.060mSvy-1) to 0.018 ± 0.002mRh-1 (1.689± 0.085mSvy-1) while the mean community radiation level ranges from 0.014 ± 0.001mRh-1 (1.183± 0.06mSvy-1) to 0.017 ± 0.001mRh-1 (1.435 ± 0.072mSvyr-1). The equivalent dose has an av...

Radiometric Survey of Aluu Landfill, In Rivers State, Nigeria

Abstract: A key component of the Millennium Development Goals is a call to halve by the year 2015 the proportion of persons without sustainable access to safe drinking water and basic sanitation in developing nations. This paper reports a study of the terrestrial radioactivity around Aluu landfill in Obiakpor Local Government Area of Rivers State, Nigeria. Measurements were carried out in the North, South, East and West directions of the Aluu landfill. An in- situ measurement was done using two well calibrated nuclear radiation meters (Radalert-100 and Digilert-50) and a geographical positioning system (GPS). Ten readings were taken in each direction of the landfill at intervals of ten (10) meters away from the landfill making a total of forty (40) sampling points. The mean site radiation levels all the four cardinal points ranges from 0.0123 0.0026 mR/hr (1.034mSv/y) to 0.0151± 0.0012mR/h (1.270mSv/y). The equivalent dose has an average value range of 1.001mSv/y to 1.270mSv/y which is slightly above the recommended dose limit of 1.0mSv/y for the general public. Comparison of the measured radiation level of site locations with the normal background levels show 21 locations representing 53% of the sampled area exceed the normal background level of 0.013mR/h. This study indicates that there is no immediate radiological health hazard for the general public, however there may be long-term health challenges. Keywords: Assessment, Dose equivalent, Landfill, Millennium, Radalert, Digilert.

GIS mapping of impact of industrial activities on the terrestrial background ionizing radiation levels of Ughelli metropolis and its environs, Nigeria

Abstract: The assessment of industrial activities and effluents on the external background ionizing radiation (BIR) levels of Ughelli metropolis and its environs has been conducted, using a digilert 100 nuclear radiation monitor and geographical positioning system for GIS mapping. The monitoring of the terrestrial BIR levels was carried out for 2 years (from May 2013 to June 2015) in 21 locations within the city and 21 other major villages/towns in Ughelli North local government area of Delta state. Measured exposure rate in Ughelli metropolis revealed a mean value of 15.20 ± 2.80 µRh−1 (1.28 ± 0.23 mSvy−1), while a mean value of 15.19 ± 2.70 µRh−1 (1.28 ± 0.23 mSvy−1) was obtained in the villages/towns. The estimated mean outdoor absorbed dose rate for the Ughelli metropolis and Ughelli environs is 132.16 ± 24.36 ηGyh−1 and 132.15 ± 23.50 ηGyh−1, respectively. The mean annual effective dose equivalent is 0.16 ± 0.03 mSvy−1) while the mean excess life cancer risk is (0.56 ± 0.11) × 10−3 mSvy−1. GIS maps of the study area revealing the BIR distribution and higher radiation levels were recorded in areas/communities where there are industrial activities and oil and gas facilities. The overall results of the measured exposure rates and the estimated radiological indices show that 73.5% of the sampled location exceeded their permissible limits. The mean equivalent dose rate obtained is higher than the safe exposure limit of 1.0 mSvy−1) recommended by UNSCEAR, and the mean radiation exposure levels in the study area is well above the normal background radiation level of 13.00 µRh−1 which shows that the studied area is radiologically contaminated. Though these values obtained may not cause immediate health hazard, there is the likelihood of long-term accumulating health side effects on the residents of some of these locations and communities sampled. Recommendations are made on the possible ways of reducing the impacts on the populace.

Natural Radioactivity Levels in Surface Soil of Ogba/Egbema/Ndoni Oil and Gas Fields

Abstract: The activity concentrations and the gamma-absorbed dose rates of the terrestrial naturally occurring radio nuclides viz. 226Ra, 232Th and 40K were determined in soil samples collected from twelve oil fields and their host communities, using gamma ray spectrometry. The soil activity ranges from 10.10 to 41.23 Bq/kg for 226Ra, 7.42 to 30.31 Bq/kg for 232Th and 92.42 to 482.79 Bq/kg for 40K with mean values of 19.16, 21.26 and 224.29 Bq/kg, respectively for host community soil. In the field soil sample, the activity concentration ranges from 16.27 to 52.19 Bq/kg for 226Ra, 9.72 to 34.13 Bq/kg for 232Th and 134.50 to 395.15 Bq/kg for 40K with mean values of 29.61, 17.41 and 262.63 Bq/kg, respectively. The concentrations of these radionuclides are compared with the values of the control samples and the UNSCEAR, 2000 standards of 35.0, 30.0 and 400 Bq/kg for 226Ra, 232Th and 40K respectively. The measured activity concentration of 226Ra, 232Th and 40K in soil is lower than the world average except in two oil fields that 226Ra and 40K exceeded the world average. Radium equivalent activities are calculated from the results to assess the radiation hazards arising due to the use of these soil samples in the construction of dwellings. All the soil samples have radium equivalent activities lower than the limit set in the UNSCEAR report (370 Bq/kg). The overall mean outdoor Absorbed Dose rate are 32.17 and 35.45nGy•h−1 respectively for host community soil and field soil samples. The corresponding effective dose calculated has mean values less than 1.0 mSvy-1, the limit set by WHO (2008). The hazard indices calculated were all less than unity (1) showing that all the soil/sediment samples sampled are still safe for building purpose since their radiological impact is minimal. The percentage contribution of each of these radionuclide are; 64.77% for radium-226, 3.13% for thorium-232 and 32.10% for potassium-40. The entire radiation hazard indices are within the acceptable limit therefore, no immediate health risk as a result of these radionuclide but continuous exposure may result to a significant health impact.

Environmental Radioactivity From Natural Industrial And Military Sources

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Concentrations of TENORMs in the petroleum industry and their environmental and health effects

Abstract: Crude oil and its products and wastes are among the significant sources of naturally occurring radioactive materials (NORMs). These materials may be enhanced to high levels due to technological and human activities, which are called technologically enhanced naturally occurring radioactive materials (TENORMs). Thus, the average radioactivity of these radionuclides sometimes exceeds the exemption level of 10 000 Bq kg−1, which is recommended by the IAEA's safety standards. TENORMs in the oil and gas industry may generate greater radioactivity levels, which eventually represents potential environmental and health risks. This will require continuous attention by monitoring and surveillance during routine processes in the petroleum industry. In this paper, a comprehensive review of the published literature is conducted to evaluate the TENORM concentrations in the oil and gas industry. Moreover, their environmental and health hazards in different regions of the world are discussed.

Radiation hazard indices and excess lifetime cancer risk in soil, sediment and water around mini-okoro/oginigba creek, port harcourt, rivers state, nigeria.

Abstract: 40 K. The ratio of Th/U for water, sediment and soil samples ranged from 0 to 7.63, 0.54 to 4.72 and 0.17 to 3.64 respectively. Whereas, the ratio K/U and K/Th ranged from 0 to 0.33, 0 to 1.66 and 0.01 to 0.87 and 0.04 to 0.16, 0 to 0.35 and 0.01 to 0.77 for water, sediment and soil respectively. To assess the radiological hazard of river sediments, water and soil ,the radiological hazard indices such as absorbed dose rate, annual effective dose equivalent (AEDE), hazard indices (Hin and Hex),activity utilization index (I), annual gonads dose and excess lifetime cancer risk (ELCR) were calculated and found to be below the internationally recommended values. The contribution of 238 U, 232 Th and 40 K to the effective dose were 56.9%, 27.2% and 15.9% respectively in water, 33.6%, 21.2% and 45.2% respectively in sediment and 71.8%, 14.2% and 14.0% respectively in soil. The results indicate that the radiation hazard from primordial radionuclide in all river water, river sediments and river bank surface soil samples from the area studied is not significant. Therefore there is no immediate radiation health hazard associated with the use of any of the samples studied.